See Also

The study, supported by the US National Institute on Alcohol Abuse
and Alcoholism (NIAAA) was conducted by Dr. William Kerr and colleagues
and is published in the journal Alcoholism: Clinical and Experimental
Research.

Although the proportion of wine, distilled spirits and beer are
different, standard drinks of each contain comparable amounts of
alcohol -- about six-tenths of one ounce of alcohol. Standard drink
refers to a 12 ounce can or bottle of beer, one-and one-half ounces
of 80 proof distilled spirits (straight or in a mixed drink), or
five ounces of wine. To a breathalyzer they’re all the same.

Reference:

Kerr, William C., Greenfield, T. K.,
and Tujague, J. Estimates of the mean alcohol concentration of the
spirits, wine and beer sold in the US and per capita consumption:
1950 to 2002. Alcoholism: Clinical and Experimental Research,
2006, 30(9), 1583-1591.